On Wednesday, Google announced that it would start limiting the abilities of political advertisers to target their messaging in the coming months.

In a blog post, Google’s vice president of product management and advertising Scott Spencer, said that the company would begin to ban political advertisers from targeting consumers based on their political affiliation or public voter records. Advertisers will still be able to target voters based on age, gender and zip code, but no more specific location targeting will be permitted. Contextual advertising, like “serving ads to people reading or watching a story about, say, the economy,” Google said, will also be permitted.

These changes will roll out in the United Kingdom ahead of its general election by the end of this year, and globally on January 6, 2020.

“We’re proud that people around the world use Google to find relevant information about elections and that candidates use Google and search ads to raise small-dollar donations that help fund their campaigns,” Spencer said in a statement. “But given recent concerns and debates about political advertising, and the importance of shared trust in the democratic process, we want to improve voters’ confidence in the political ads they may see on our ad platforms.”

In October, Twitter CEO Jack Dorsey announced in a tweet thread that the company would move to ban all political advertising on November 22nd. On Friday, Twitter released more guidelines, limiting how cause-based advertisers, like climate change and pro-choice advocacy groups, coudl target their ads.

Google’s new restrictions mirror Twitter’s policy in many ways, although Google stops shy of a blanket ban on political advertising. Still, the changes are likely to have a severe and immediate effect on the ad ecosystem, given the immense scale of Google’s ad network in comparison to Twitter. In the US alone, the company has run more than $127 million in political ads since June of 2018.